Safe edge metal grommet



v Aug. 9, 1966 c. OLSON I SAFE .EDGE METAL GROMMET Original Filed Oct.'7, 1963 Inventor. Conrad 024070. b a PM United States Patent 3,264,677SAFE EDGE METAL GROMMET Conrad Olson, Arlington, Mass, assignor toUnited-Carr Incorporated, a corporation of Delaware Original applicationOct. 7, 1963, Ser. No. 314,460. Di-

vided and this application Nov. 13, 1964, Ser. No.

4 Claims. (Cl. 16-2) flict between two features which were almostuniversally sought but never satisfactorily provided inmetal grommets,many manufacturers in recent years converted to the use of rubber orplastic grommets as the utilization of these materials became moreextensive.

Specifically, the two features desired were: (1) totally smooth surfaceson the grommet in those areas with which an article passed through thegrommet might come in contact and (2) some form of snap-in,self-retaining fastening means provided as a part of the grommet.

The procedure to date has generally been to provide the desired snapfastener retaining means as part of a onepiece device by cutting awayportions of thedevice to form flexible fingers or tabs for engaging asupport and therein lies the inherent difficulty in that cutting themetal most often results in sharp, burred edges which are capable ofdamaging the material of an article held in the grommet. Such acondition is of course particularly undesirable Where an insulatedconductor is to be passed through the device.

Patent No. 2,239,255 is illustrative of the type of device and method offorming same contemplated by the foregoing remarks.

The alternative of course is to attach a separate fastening means to thedevice but since this obviously results in an increase in cost, ergo anincrease in price, many industries as previously indicated havepreferred to use rubber or plastic grommets in lieu of the metalvariety.

The fact that devices made of molded .plastic or rubber would generallypossess smooth, imperforate surfaces and the desired flexibility forsnap fastening is rather obvious and requires no further explanation.However, such materials, as compared with' metal, have other wellknowncharacteristics which render them somewhat deficient for use in certainapplications.

Primarily, of course they generally lack the strength of most metals.Admittedly this is not always true in some of the harder plasticsbut theharder plastics lack flexibility and are likely to crack if subjected tocontinuous shock and vibration, in particular when used on automotivevehicles.

On the other hand grommets made of rubber and the more resilient.plastics have a tendency to fray and Work loose when subjected tosimilar conditions.

Thus when viewed in the light of the prior art relating to one-piecegrommets it is readily seen that the device of the present inventionrepresents a significant advance in the art.

Specifically invention is seen to abide in the concept of cutting legsor fingers from a'preformed flange, flaring the body portion of thegrommet to form a second flange acting as a stop and thence bending thelegs or fingers to form snap fastening means as a part of the grommet,thereby providing the desired combination of smooth,

ice

unburred surfaces adjacent the entrances to the grommet and integralsnap fastening means.

Thus the specific objects of the invention are as follows: I

(1) To provide a novel, inexpensive, one-piece, metal protection device;

(2) To provide a one-piece, metal protection device having totallysmooth surfaces over all areas of the device with which an article to beprotected by it might come in contact;

(3) To provide a one-piece, metal protection device havingself-retaining fastening means formed as a part of the device and havingtotally smooth surfaces over all areas of the device with which anarticle being held by it might come in contact.

The invention will be more clearly understood from the followingdetailed description when read in conjunction with the accompanyingdrawings in which:

FIG. 1 is a top plan view of the device;

FIG. 2 is a side elevation of the device;

FIG. 3 is a bottom plan view of the device;

FIG. 4 is an installation in section depicting the device afiixed to asupport having cables passed therethrough.

The invention has been depicted in the form of a selfretaining grommetas a convenient form of disclosure.

As best shown in FIGS. 1 through 4 the tubular body portion 1 of thegrommet 2 has a central aperture 3 throughout its length. The flange 4is disposed at one end of the body portion 1 and optionally has a bead 5formed on its periphery.

A smaller flange 6 is located at the opposite end of the body portion 1.

The fastener legs 7 are integral at one of their ends with the flange 6.The legs 7 are bent away from flange 6 in the direction of flange 4 andare spaced from the body portion 1 as best shown in FIGS. 2 and 4. FIG.4

shows one end of the legs 7 as being adjacent flange 4 but not incontact with the flange. The legs 7 have been,

bent in diverging and thence converging directions with respect to thebody portion 1 to form shoulders 8. The flange 4 as shown in FIG. 4 hasbeen bent on itself towards flange 6 so as to partially enclose the endsof the legs 7 adjacent the. flange 4. I

An installation of the grommet 2 attached to an apertured support 9having two cables 10' passed through the central aperture 3 is depictedin FIG. 4. In installation the grommet 2 is inserted in the aperture 11in the support 9 with the end adjacent the flange 6 leading. The leadingends of the legs 7 yield until the shoulders 8 of the legs have clearedthe opposite side of the support 9 and then spring back to their normalposition with shoulders 8 gripping the'undcrside of the support 9 andsecuring the grommet thereto. The diameter of-the aperture 11 in thesupport 9 is something less than the distance between the shoulders 8 ofany two opposite legs 7 and the flange 4 acts as a stop to prevent thegrommet 2 from passing completely through the aperture 11 in thesupport. Obviously the device may be made in a variety of lengths toaccommodate supports of ditferentthicknesses. As further shown by FIG. 4the wire 10 as it enters and leaves the grommet rides on the smoothinternal edges of the flanges 4 and 6. Obviously since both flanges areto a degree bent back on themselves the cables 10 will always contactonly smooth, unburred surfaces regardless of the direction from whencethey come prior to entering the aperture 3 in the grommet 2.

With reference to the foregoing descriptions'it is to be understood thatwhat has been disclosed therein represents only a single embodiment ofthe invention, for example, it is contemplated that the tubular bodyportion of the grommet might be embossed or partially broken out to formthe fastening means, and is to be construed as illustrative rather thanrestrictive or limiting in nature and (its: outer circumferentialedggyisZ bent downwardly and that the scope of the invention is bestdescribed by the following claims. 7

What is claimed: 14A one-piece"sheetrmetali grommet' comprising ahollow,. continuous, generally circular, -open end body portion,- afirstflange operable as a stop :e'xtending outwardly from one endof said'bodyportion, a second flange extending outwardly from thefopposite. end ofsaid body portion; each of said flanges presenting .a continuoussmoothlsurface adjacent said-ho1low=body portion,: and aplurality ofsnap acting legs'integral with :aidsecond flange and idisposedabout theperiphery of; said: body portion in spaced relation therewith; said legsextending toward said first flange and'termin-ating in;a free end-in;spaced relationship therewith and havinga length at least as great'asone'half'the length of said body portion.

2. A one-piece sheet metal grommet according to claim i 1 wherein saidfirst flange overlies the ends of. said legs toward said .legs.;

3. A one-piece sheet-metal grommet-according to claim 2'Ewhereinportions of' said first fla'nge and the terminal i free endsof-saidilegslie :inka common,=imagina ryradial plane extending outwardly from saidbody portion."

4. A one-piece sheet metal grommet according totclaim V 1 wherein saidfirst'fiange'has ahead formed :on ;the outer pcripheraliportion thereof:g

ReferencesrCit'ed by't hej Examiner UNITED f' STATES E PATENTS EDWARD.C; :ALLEN; Primary Examiner. D. L. TROUTMAN, AssistantsExaminer. g

1. A ONE-PIECE SHEET METAL GROMMET COMPRISING A HOLLOW, CONTINUOUS,GENERALLY CIRCULAR, OPEN END BODY PORTION, A FIRST FLANGE OPERABLE AS ASTOP EXTENDING OUTWARDLY FROM ONE END OF SAID BODY PORTION; A SECONDFLANGE EXTENDING OUTWARDLY FROM THE OPPOSITE END OF SAID BODY PORTION,EACH OF SAID FLANGES PRESENTING A CONTINUOUS SMOOTH SURFACE ADJACENTSAID HOLLOW BODY PORTION, AND A PLURALITY OF SNAP ACTING LEGS INTEGRALWITH SAID SECOND FLANGE AND DISPOSED ABOUT THE PERIPHERY OF SAID BODYPORTION IN SPACED RELATION THEREWITH, SAID LEGS EXTENDING TOWARD SAIDFIRST FLANGE AND TERMINATING IN A FREE END IN SPACED RELATIONSHIPTHEREWITH AND HAVING A LENGTH AT LEAST AS GREAT AS ONE HALF THE LENGTHOF SAID BODY PORTION.